interestingly, as i was contemplating downsizing to 18's for comfort, the difference in wall height is only 16.5% compared to 19's, so i don't know if that would be noticeable. certainly not as much as just changing to non-rft's and keeping the same wheel size

edit:
SCBMW02. I just worked out that with your rears you have increased the side by 6mm, and fronts by 3.5mm which is halfway between the gain made by 18's on the rear (12.75mm normal difference) and less than a third on the fronts (11.25mm normal) but probably messed up your speedo?

interestingly, as i was contemplating downsizing to 18's for comfort, the difference in wall height is only 16.5% compared to 19's, so i don't know if that would be noticeable. certainly not as much as just changing to non-rft's and keeping the same wheel size

edit:
SCBMW02. I just worked out that with your rears you have increased the side by 6mm, and fronts by 3.5mm which is halfway between the gain made by 18's on the rear (12.75mm normal difference) and less than a third on the fronts (11.25mm normal) but probably messed up your speedo?

I can only speak for my experience with my 1'er at this point, but the PSS tires really transformed the car. Much better ride quality and grip. Initial turn in might have been a bit more imprecise, but that could just be me. Can't wait to get them on the Z4. For the life of me I can't understand why BMW sees fit to handicap their higher performance cars with these things.

I don't know whether the chemistry of the kits is different but the general idea is that they inject a "goop" into the tire which is supposed to form a seal that holds air in when the "goop" gets hotter, and there is an air compressor incorporated that inflates the tire.

What ended up happening to me (1/4" nail puncture in the center of tread block, nail still embedded) is that the "goop" didn't actually form a seal and the air loss wasn't stopped at all. I had to overinflate the tire and cross fingers there was enough air to get to a tire shop.

I've also heard the "goop" ruins the TPMS but I have no first hand experience because this was on a non TPMS car.

EDIT: personally, I think the BMW kit is a rebrand of slime or some other similar product at a big mark up, and i wouldn't trust it. I don't have tech to back that up but that's my opinion and the reason i stick with RFT

I don't know whether the chemistry of the kits is different but the general idea is that they inject a "goop" into the tire which is supposed to form a seal that holds air in when the "goop" gets hotter, and there is an air compressor incorporated that inflates the tire.

What ended up happening to me (1/4" nail puncture in the center of tread block, nail still embedded) is that the "goop" didn't actually form a seal and the air loss wasn't stopped at all. I had to overinflate the tire and cross fingers there was enough air to get to a tire shop.

I've also heard the "goop" ruins the TPMS but I have no first hand experience because this was on a non TPMS car.

EDIT: personally, I think the BMW kit is a rebrand of slime or some other similar product at a big mark up, and i wouldn't trust it. I don't have tech to back that up but that's my opinion and the reason i stick with RFT

That BMW Mobility kit is the same one that they put in all of the M cars. Interesting that they don't fit RFT's on the M cars, that tells you something. I figure if its good enough for the M cars its good enough for me, but agree, hope I never need to use it.

Anyway, I got the PSS's installed the other day. They are great, the increased grip is amazing, ride nominally smoother. They seem to have slightly higher road noise, which is opposite of my experience with them in my 135i. I have not fooled around with pressures yet, but will.

No fit issues with the 235/35/19 fronts and 265/30/19 rears. They fill in the wheel wells a little better too.

That BMW Mobility kit is the same one that they put in all of the M cars. Interesting that they don't fit RFT's on the M cars, that tells you something. I figure if its good enough for the M cars its good enough for me, but agree, hope I never need to use it.

Anyway, I got the PSS's installed the other day. They are great, the increased grip is amazing, ride nominally smoother. They seem to have slightly higher road noise, which is opposite of my experience with them in my 135i. I have not fooled around with pressures yet, but will.

No fit issues with the 235/35/19 fronts and 265/30/19 rears. They fill in the wheel wells a little better too.

Shame the ride is not a big difference
What about he speedo? Any change? And if so is it a higher or lower reading?

Shame the ride is not a big difference
What about he speedo? Any change? And if so is it a higher or lower reading?

Don't get me wrong, the ride is clearly smoother.

Not sure about the speedo, I'll need to check. As the diameter is slightly larger, it may be a little low. In my experience, BMW calibrates the speedos on the high side anyway, so it may actually be MORE accutate than before.

Not sure about the speedo, I'll need to check. As the diameter is slightly larger, it may be a little low. In my experience, BMW calibrates the speedos on the high side anyway, so it may actually be MORE accutate than before.

Anyway, I got the PSS's installed the other day. They are great, the increased grip is amazing, ride nominally smoother. They seem to have slightly higher road noise, which is opposite of my experience with them in my 135i. I have not fooled around with pressures yet, but will.

Do you have any lap times or other data on the stockers vs. PSS? I'm on the fence due to lack of spare and haven't been able to find data on the change. "feel" can be misleading sometimes and I need some tech to convince me to take on the the risk of needing a flatbed to get home.

Do you have any lap times or other data on the stockers vs. PSS? I'm on the fence due to lack of spare and haven't been able to find data on the change. "feel" can be misleading sometimes and I need some tech to convince me to take on the the risk of needing a flatbed to get home.

No hard data. I don't track my car. Do some searches on these tires, and I think you will find others echo my comments. The car clearly has more grip than with the rft's, and the lack of super stiff sidewalls help smooth out the ride. Its quite obvious if you were to drive them back to back. No sure about the flatbed issue, I think the mobility kit will me get to a shop if needed.

You can lookup the diameter of various size and make of tires to determine the variable to plug into the formula. Diameters vary by tire manufacturers for the same sizes. It's not an exact science as temps and pressure are variables to acknowledge.
I used the PSS 19" diameter for 265-30 for the following graphic of a spreadsheet.

Not sure about the speedo, I'll need to check. As the diameter is slightly larger, it may be a little low. In my experience, BMW calibrates the speedos on the high side anyway, so it may actually be MORE accutate than before.

My speedo is already slow by about 3 mph

All our analog speedos over rate by 6%. It's been shown over and over. But, there is a fix.

Coding:
It is pretty easy to have someone activate the digital velocity indicator in the car and then tell the car to show the actual mph. The analog gauge will read high, but your digital will be right on. There are Indy shops that'll do this as well as a few guys remotely. Check out the E90 page-coding forum and you'll find all kinds of other cool things you can turn on for our cars.